Some kinds of injectable medical drug are highly toxic, or it may for other reasons be undesirable that patients or health care personnel come into contact with the medical drug or fumes originating from the medical drug, except for the actual administration of the drug. One example of such kinds of drugs are those used for oncology treatment. Another example is drugs which are stored in dry form, e.g. lyophilised drugs, and which need to be reconstituted by mixing the dry drug with a liquid diluent prior to administration of the drug.
Drugs which are stored in dry form and need to be reconstituted prior to administration are sometimes stored and administered by means of a dual chamber syringe. In such syringes the dry drug and the diluent are stored in separate cavities. When it is desirable to deliver the drug, the syringe is initially operated in order to bring the dry drug and the diluent into contact, thereby causing reconstitution of the drug. Subsequently, the syringe is operated in order to cause the reconstituted drug to be delivered from the syringe. Following the reconstitution of the drug, a relatively large amount of air or gas is sometimes present in the syringe. Such air or gas must be removed from the syringe before administration of the drug, in particular in the case that the drug is to be injected. To this end a so-called air shot is performed. However, in the case that the drug produces fumes which are toxic or the like, it is important that the air shot is contained in order to ensure that the fumes, and possible liquid waste, are disposed of in a controlled and responsible manner.
In some prior art injection systems, health care personnel must manually manipulate various parts of the injection system, in order to cause the drug to be injected, and possibly in order to cause reconstitution of the drug and/or air shots. This introduces the risk that the health care personnel and/or the patient come into contact with the drug, and/or that the drug and/or fumes originating from the drug are spilled.